People are generally aware of the most common causes of hallucinations, like schizophrenia and a really high fever. But lesser known are the more rare causes; here are six you probably haven't heard about.

The term “serial” often brings to mind a person whose actions are of a negative nature — serial killers, rapists, etc. — but there’s a new type of person whose actions of a serial nature are a bit more laughable: the serial sleep-texter.

The average American teenager sent 3,339 texts a month in 2010, eight percent higher than the year before, a Nielsen survey found. Meanwhile, young adults, ages 18-24, sent out almost half as much at 1,630 per month. It’s a technological age, and just like many people before the advent of text messaging found themselves picking up their landline phone in the middle of the night, anecdotal evidence is growing as people report late-night, half-asleep text messages — many of which they don’t remember sending.

Serial Sleep-Texting In All Its Glory

“My charger is right there in the corner so sometimes I would keep it here next to me. I guess I got up and texted and went back to bed but I don’t remember it,” sleep-texter Megan, who didn’t give her last name, told CBS. “Four o’clock in the morning, three o’clock in the morning, it would just be a sentence of jumbled up stuff.”

But while Megan reported sending incoherent messages, others can be much more understandable and humorous. Kayla Potega, 23, rarely sleep-texts, but when she does, the messages always sent to her boyfriend, CNN reported.

“I think it’s driven by the fact that I want to tell (my boyfriend) these dreams, but I’m still kind of asleep, so I just reach for the phone and text him regardless of what it is, and I have no recollection of doing it at all,” she told CNN. “The last one, I remember I was trying to give him some sort of advice … It ended up being something like, ‘just because your brain is a cast iron skillet, doesn't mean your body is.'”

Other people might not get such a laugh out of their sleep-texts. One girl studied by Elizabeth Dowdell, a professor of nursing at Villanova University, tended to send overly romantic sleep-texts.

“A classmate texted her something about anatomy class, and her reply back was, ‘I just love it. I love you! You’re the light of my life,'” Dowdell told U.S. News & World Report. “Then, there was an old boyfriend who texted her, and she sent responses like, ‘I adore you, please come over,’ while she was asleep. She was mortified.”

Sleep-Texting's Health Consequences

The trend is particularly common among adolescents and teens, Dowdell says, and there can be health-related consequences because of it. At an age when sleep is important — the Centers for Disease Control and Prevention recommends at least eight-and-a-half hours for teens — keeping a cell phone close during the night could make it difficult to fall into REM (rapid eye movement) sleep.

“Sleep is a very important restorative process,” sleep specialist Dr. Josh Werber told U.S. News & World Report. “And when we’re not fully engaged in it, and not getting the amount we need, we’re not having the same restorative effects on our brains — and that affects our cognitive ability the next day.”

After a night of sleep-texting, Laura Hogya wakes up “exhausted the next day, and I don’t know if it’s from tossing and turning, or answering a text message,” she told CBS. “If I answer a client e-mail — that’s something I have to worry about.”

Simply having a cell phone close by at night may be enough to disturb sleep. Light emitted from phones can cause the brain to produce less melatonin, thereby throwing off the circadian rhythm and causing the brain to think it should stay awake. The best way to ensure sleep-texting never happens is to turn any electronics off one hour before going to bed, Werber said.

#SleepTexting

Searching #sleeptexting on Twitter produces some great results. Here are some:

· I long hiixxx. That’s what I’ve guy huh

· I’m gonna sleep the game blue more its study

· The cat is still meowing at the door. It makes you wonder what they do out there. Like there’s an all-night cat party and they have to get there

· Are you serious about this cow statue? It can’t stay in the front yard we’ll get arrested